-LRB- CNN -RRB- -- Taryn Lopez does n't think it got too terribly cold during the two days she was stranded on Alaska 's Mount Mageik volcano .

`` I think about 28 degrees was the lowest we saw -- but then the temperature gauge was frozen , '' she said Saturday evening from King Salmon , Alaska .

Thanks to sleeping bags , waterproof gear and emergency supplies , Lopez , a fellow researcher and a pilot survived unharmed in their iced-over helicopter from Wednesday until a rescue chopper scooped them up Friday .

Pilot Sam Egli took John Paskievitch , a geophysicist with the U.S. Geological Survey , and Lopez , a post-doctoral researcher , about 6,500 feet up the volcano on Wednesday .

The researchers were picking up instruments to save them from the upcoming winter . Their work is aimed at learning how seismic readings are linked to the underlying causes of earthquakes . Some volcanic earthquakes quakes are caused by moving magma , water or gas , Lopez said . Knowing which substance is moving could help assess the risk of eruptions , she said .

The trio took advantage of a break in the weather Wednesday to land at their highest instrument site on Mageik .

`` There were blue skies when we landed , '' she said . But within half an hour , Egli told the researchers he was concerned about ice on the rotors .

`` We grabbed our stuff and got in the helicopter , '' Lopez said , but even in the few minutes that took visibility became too poor for takeoff .

Egli could call for help by satellite phone and radio , but the weather prevented a rescue attempt on Wednesday . On Thursday , rescuers circled overhead but could not land .

Meanwhile , the three stayed in sleeping bags inside the helicopter except to answer nature 's calls and shoot a flare at the request of the rescuers . There was enough food and water on board .

`` Even though it was n't that cold , it was pretty foul when you were outside , '' Lopez said .

Lopez , 33 , grew up in Rochester , Minnesota , and has spent time on mountains in Russia and Alaska , so she was prepared for the cold . But she was grateful for Paskievitch and Egli 's decades of experience in the field .

`` I felt really luck to be with those people , '' Lopez said . `` I know they kept us all alive . ''

She also praised the Alaska Air National Guard , which rescued her .

`` It was such a relief hearing them up there even when they could n't get in , '' she said .

Paskievitch was n't available to talk Saturday -- because he was back out on the mountain . Lopez said he hoped to check on the condition of the helicopter , where the researchers had to leave their instruments .

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NEW : Rescued researcher describes two days in sleeping bags inside chopper

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NEW : Research aimed at improving assessment of risks of eruption

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Trio stranded 6,500 feet up Mount Mageik

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They had emergency provisions and were rescued unharmed